MVC custom serialization of List<X> parameter for GET request?

Question

I'm wanting to change a request to be GET instead of POST so users can share the generated URLs.
The current system uses a normal form submit and takes advantage of the automatic serialization between the form submit and the MVC ActionResult for a List of custom objects.

e.g.

<form action="/MyPage">
  <input type="hidden" id="MyThings_0__Value" name="MyThings[0].Value">
  <input type="hidden" id="MyThings_0__Flag" name="MyThings[0].Flag">

  <input type="hidden" id="MyThings_1__Value" name="MyThings[1].Value">
  <input type="hidden" id="MyThings_1__Flag" name="MyThings[1].Flag">
</form>

However doing it this way causes the GET string generated to be overly long and complicated. This is bad because the MyThings list can be up to 10 items long.

http://myurl.com/MyPage?MyThings%5B0%5D.Value=ThisIsValue1&MyThings%5B0%5D.Flag=1&MyThings%5B1%5D.Value=ThisIsValue2&MyThings%5B1%5D.Flag=2

I was hoping for the string to appear more user-friendly. Something like:

http://myurl.com/MyPage?MyThings=ThisIsValue1-1,ThisIsValue2-2

Can this be done with custom serialization? And if so, how would I go about implementing it?

My Model and ActionResult:

namespace MyNamespace {

    public class MyThing {
        public string Value { get; set; }
        public int Flag { get; set; }
    }

    public class Filter {
        public string CustomAttribute1 { get; set; }
        public string CustomAttribute2 { get; set; }
        public string CustomAttribute3 { get; set; }

        public List<MyThing> MyThings { get; set; } = new List<MyThing>();
    }

    public ActionResult MyPage(Filter filter) {
        MyModel model = StaticMethod.GetMyModel(filter);
        return View(model);
    }

}

Answer 1

In the end I decided against using custom URL serialization and used helper methods to convert to string/class backward and forwards within the C# model.

public class Filter {

    public string MyThing { get; set; }

    public List<MyThingClass> MyThings {
        get {
            if (this._myThings == null) { // Default to Query string
                this._myThings = ToQueryList(this.MyThing);
            }
            return this._myThings;
        }
        set {
            this.MyThing = ToQueryString(value); // Automatically assign QueryString to serialized QueryItems on set
            this._myThings = value;
        }
    }
    private List<MyThingClass> _myThings { get; set; }

    public static List<MyThingClass> ToQueryList(string queryString) {
        return queryString.Split(',').Select(x => MyThingClass.FromString(x)).ToList();
    }
    public static string ToQueryString(List<MyThingClass> myThings) {
        return string.Join(",", myThings.Select(x => x.ToString()));
    }
}



public class MyThingClass {

    public string Value { get; set; }

    public int Flag { get; set; }

    /// <summary>Converts a QueryItem object to a serialized object ready for the QueryString.</summary>
    public override string ToString() {
        return string.Concat(this.Value, "-", this.Flag);
    }

    public static MyThingClass FromString(string value) {
        var v = value.Split('-');
        return new MyThingClass() {
            Value = v[0],
            Flag = Convert.ToInt32(v[1])
        };
    }
}